The systems for applying liquid coating products, in particular paint, comprise a pump suitable for aspirating the paint by creating a vacuum using a piston, so as to orient the paint toward an outlet conduit connected to a spraying device, such as a gun. Such a system requires sealing the pump body relative to the part in which the paint circulates, in order to avoid malfunctions of the pump and the introduction of lubricant into the paint, in particular during movements of the piston rod.
To that end, the application systems comprise sealing devices, also called “cartridges”. These devices comprise a metal frame mounted in a flange of the application system, an inner guide gasket and a lip seal suitable for sealably surrounding the rod of the piston of the application systems. This lip seal is pressed against the rod of the piston by metal springs forming a hollow in which the paint can accumulate and form dry deposits detrimental to the proper working of the application system.
The sealing and guide gasket must be mounted in the metal frame, which may cause damage and leaks and cause significant waste.